1. Field of the Invention
The present invention relates to an Internet protocol (IP) packet classifying method, and more particularly, to a fast IP packet classifying method invented to provide a differentiated quality of service (QoS).
2. Description of the Related Art
Most recent commonly used routers do not provide differentiated services depending on the characteristics of transferred data because they are designed to provide a simple best-effort service. For quality-controllable Internet services, a router must be able to support admission control of every incoming packet, and resource reservation, per-flow queuing, and fair scheduling of the incoming packets.
A differentiated service is established based on the rules defining the condition of incoming packets to belong to each flow, and its corresponding action. A function unit in which packets are classified according to flows and processed based on such a rule set is referred to as a packet classifier.
In practice, the rules applied to respective packet flows are managed in the form of flow tables by a router. Accordingly, in order to provide differentiated services for packet flows, every packet arrival requires a flow table search. The Internet Engineering Task Force, an Internet standard organization, advises that the flow table search should be based on 6 multiple field values of a packet header, including among others source and destination IP addresses, source and destination TCP/UDP port numbers, IP protocol type and differentiated service code point (DSCP).
However, this search based on such multiple fields for every packet arriving to a router acts as an operation load on the routing. Specifically, with an increase in the packet processing speed required, the operation load generated by the above-described packet classification also increases. This requires new approaches to reduce the operation load caused by the above-described packet classification.